Like many Z3 owners, I'd been living with the dreaded yellow ABS/ASC lights on the dashboard for some time. They'd come on intermittently, and then after the pull away self-test would go out for a variable amount of time - sometimes a few miles, other times a few days, before coming back on again. My last two MoTs included failures due to these lights, only passing because the lights went out after leaving the test centre, needing another test after one hour, a situation I wanted to avoid again.

This winter, with the car on SORN and in the garage I decided to get this licked once and for all. I bought a diagnostic cable set from bcables via eBay for about £30 and after connecting to the car, established that the ABS module was at fault. The speed sensors and pump didn't report any faults. A bit more research on this forum and online yielded bbreman as someone who could repair it, but first it has to be removed. As I couldn't find much in the way of instructions, I thought I'd write my own

First of all, to answer similar questions I've seen elsewhere, you don't need to bleed your brakes or drain the fluid. The module attaches to the pump with four torx type screws - more of that in a moment - and an electrical connector with a lever to hold it in place.

Before starting work, I had already removed the battery from the car but at the very least make sure it is disconnected. Here's the troublesome ABS module as found. You can't miss it as it lives on the left side of the engine bay (as viewed from the driver's seat):

The module is to the left of the picture, where the wires can be seen going into it. It's pretty close to the engine and so it's perhaps no surprise after many hundreds or thousands of heating and cooling cycles the module would start to suffer. Here's a close-up of the module; this picture has been rotated 180 degrees so you can see the part numbers:

Now, the bolts. They're torx type but have heads instead of being recessed into the thread. I have a couple of torx drivers but no sockets to tackle this, until I realised I could use another threaded bolt as a driver itself. I found one and added two nuts to it, then used a cyclist spanner to undo. Makes more sense in this picture:

And here it is lined up with the module:

The bolts are hardly tight and they came out easily; four in all across each four corners of the module. The module then separates from the pump:

Then the electrical connector. This had been described in other threads I've seen as a fiddly job to remove, and that's quite true. With all the dust and grime in the car's 18 years, it took a lot of wiggling and gentle use of a slotted screwdriver - rotated gently once pried into the gap - to free it off. Be patient. As it starts to move, you pull the black sleeve (pictured below) away from the module and this forces the connector out:

The approach is similar to other large connector blocks I've seen before. Then the module is out:

With bbreman, I contacted them first on eBay as the BMW ABS module isn't listed; a lady responded and told me to purchase the repair service for a similar BMW product (£129 including postage both ways) and add in the notes what I needed. The team were super-quick; I posted the module on a Monday (UPS pick-up) and it was back home on Friday! Can't get faster than that really.

The modules are sealed at manufacture, so it has to be opened for repair. When the module returned, you can see where it had been re-sealed, along with a trusty-looking warranty seal sticker in place:

In the classic Haynes style, refitting is the reversal of removal. Do the connector first and then the bolts, taking care not to over-tighten. Take time to clean everything though - I used dry paper towels as the idea of using any fluid around this area didn't seem a good idea. Once done, when switching the ignition on, the lights went straight out after just a few seconds, and stayed out! I thought I'd need to drive the car to get the self-test to run, but no such problem.

I contacted bbreman to thank them and asked what repairs had actually taken place. They were vague, perhaps because someone in their office answered the query instead of an engineer, saying that "a number of components were worn and required replacement". The theory of cracked solder joints is probably the best guess, but in a way I don't mind - it's fixed, I have a warranty on the repair, and the car sailed through its MoT this week.

I have also done an ABS module in the last week and that makes my second in total.

In both cases I bought a module off of ebay for around £30-£40. In both cases they were off BMWs other than Z3s. And to be honest if they are off a Z3 they still need the following issue addressed.

Any module with the correct part number will make the issue go away. But if it's not coded correctly it could render the system useless when you most need it. The module and pump each have their own part number that doesn't appear in realoem. There is only the part number for the whole remanufactured unit. So you need to read the part number off the module and match it to the auction details. These modules can be made in France or Mexico but I'm not aware of any differences.

On the first car I did I chickened out of coding.

On the latest car I coded it. Having gone via an airbag module code a few months ago. The big deal is getting a laptop set-up with INPA & NCS Expert. Once you have that you backup the old coding, swap modules then code the new module with the backup file. You can also manually hack the file or use NCS Dummy to help. In that case you are changing the individual flags. By way of example there is a setting to say if you have a Limited-slip diff. My donor module didn't. My Z3 it is was going in did.

So coding is vital! But you've avoided this issue by paying BBReman. And I have to say £129 is not too unreasonable, especially as I always thought it was around £200. You have something now that should last another 15-20 years. I have something for 25% of the cost but that could keel over again in a few months time. But then I'm happy enough with that approach.

So coding is vital! But you've avoided this issue by paying BBReman. And I have to say £129 is not too unreasonable, especially as I always thought it was around £200. You have something now that should last another 15-20 years. I have something for 25% of the cost but that could keel over again in a few months time. But then I'm happy enough with that approach.

Interesting points. I did consider trying the repair myself, as there are one or two guides that detail how to open up the module with a dremmel and rework the solder. But it's not an area of my expertise, so trusted it for repair.

Incidentally, the repair service on eBay for generic BMW ECUs was up for £159 or Best Offer. I put an offer in of £129 because I had £29 left in my PayPal account and thought it would then leave me with a nice round £100 cost! The team at bbreman kindly accepted this offer but it may be worth getting in touch with them first.

Thanks very much for your detailed description. I don't have these problems on my Z3 - yet! But knowing what can be done and who can help is enormously reassuring. I have bought a C110 scanner which was able to clear a SRS fault on my car after I had removed and replaced the seats, but I wish I had known about the bcables software at the time.

Regarding re-coding. See this post on the other Z site https://zroadster.org/threads/abs-and-a ... ost-329296. Post 6 gives a step by step guide; basically you use the Bcables software to copy the codes for your car from one ECU module and load them into the ABS module. Very straight forward, took longer to get the PC and cables out than do the actual recoding.

It is - the coding for the ABS module is also stored in the DME. When I got my Z3 someone had obviously swapped out the ABS module and hadn't recoded it, so they just took the warning bulb out of the dash! Anyhow, I used DIS to recode the ABS module to the car, which just pulled the stored config from the DME and wrote it to the ABS.